scourge of the forest,
mound-builder ants
are afriend to man
DRAGON SLAYERS of the insect
world, Europeanwood ants surround
and kill a sawfly larva of the genus
Diprion, one of the 100,000 insect larvae
the colony, numbering a million
workers, may consume in a single day.
Such sweeps occur in the neighborhood
of the distinctive home mound that a
colony structuresfrom twigs, pine
needles, and bark. Started atop a stump,
it may rise to a height of two meters.
Its materialsand shape encouragerunoff
of rainwaterand insulateits many
chambers during long Europeanwinters,
when the body heat of the ants keeps
it warm. Several hundred queens
reside here. Newly mated females return
each spring to their own or a neighbor
mound. In summer the overcrowdedcolony,
like a cell, divides, and a number of
queens, each accompanied by several
thousandworkers, move nearby to
start new mounds.
Because the wood ants serve as a
biologicalcontrol on forest pests,
Europeansfor years have valued them.
Several nations have passed laws against
harming the nests. Foresters often cover
the mounds with screen to keep out
woodpeckers and to discouragehumans
who would mine pupae for fish and bird
food. Nests are often collected by the
barrelful and trucked to otherforests
where wood ants have disappeared. Q
FORMICAPOLYCTENA,ABOUTTEN TIMES LIFE-SIZE
ILLUSTRATIONS TEXT BY
ALICE J. HALL
NATIONAL GEOGRAPHIC SENIOR STAFF
813